Answer:
k = 9
Step-by-step explanation:
3x - y = 10 ______( 1 )
kx - 3y = 30_____( 2 )
( 1 ) × 3____ 9x - 3y = 30_____( 3 )
[tex](3) - (2) \\9x - 3y - (kx - 3y) = 30 - 30 \\ 9x - 3y - kx + 3y = 0 \\ 9x - kx = 0 \\ x(9 - k) = 0 \\ 9 - k = \frac{0}{x} \\ 9 - k = 0 \\ 9 = k \\ [/tex]
